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Up until now, logical replication actions have been performed as the subscription owner, who will generally be a superuser. Commit cec57b1a0fbcd3833086ba686897c5883e0a2afc documented hazards associated with that situation, namely, that any user who owns a table on the subscriber side could assume the privileges of the subscription owner by attaching a trigger, expression index, or some other kind of executable code to it. As a remedy, it suggested not creating configurations where users who are not fully trusted own tables on the subscriber. Although that will work, it basically precludes using logical replication in the way that people typically want to use it, namely, to replicate a database from one node to another without necessarily having any restrictions on which database users can own tables. So, instead, change logical replication to execute INSERT, UPDATE, DELETE, and TRUNCATE operations as the table owner when they are replicated. Since this involves switching the active user frequently within a session that is authenticated as the subscription user, also impose SECURITY_RESTRICTED_OPERATION restrictions on logical replication code. As an exception, if the table owner can SET ROLE to the subscription owner, these restrictions have no security value, so don't impose them in that case. Subscription owners are now required to have the ability to SET ROLE to every role that owns a table that the subscription is replicating. If they don't, replication will fail. Superusers, who normally own subscriptions, satisfy this property by default. Non-superusers users who own subscriptions will need to be granted the roles that own relevant tables. Patch by me, reviewed (but not necessarily in its entirety) by Jelte Fennema, Jeff Davis, and Noah Misch. Discussion: http://postgr.es/m/CA+TgmoaSCkg9ww9oppPqqs+9RVqCexYCE6Aq=UsYPfnOoDeFkw@mail.gmail.com
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.